CH. X] 



THE CONDITIONS OF LIFE IN THE SEA 



217 



in the sea, and that these are of such a nature as to serve as the 

 food-stufFs, not only for marine bacteria, but also for some of 

 the lower invertebrates. I believe that these results are quite 

 novels 



Amount of carbo7i compounds, in m,iUigrammes, contahied in 

 one litre of sea water from the Bay of Naples. 



Phosphoric acid. This substance is present in the sea in 

 the form of soluble phosphates of calcium. Its exact estimation 

 is attended by particular difficulties, and the older analyses of 

 Schmidt are probably inaccurate. Schmidt- found that there 

 were from 2'3 to b'Q parts per million of calcium phosphate in 

 solution in the warmer seas (Suez Canal, Indian Ocean and South 

 Chinese Seas), and 8*6 to 16*6 parts per million in solution in the 

 colder seas (North Polar, and Norwegian), results not easily to be 

 explained. Raben, however, found that the amount of phosphoric 

 acid in the sea was very much less, and that it underwent a slight, 

 though distinct seasonal variation-'. His analyses were made on 

 samples of sea water collected by the Poseidon during the seasonal 

 cruises, and gave the following results : 



Feby. and May, 1904, 014 to 0'25 mgrs. per litre of P.Og 

 August „ 1-46 



Silica. The amount of dissolved silica in the sea is so small 

 that its exact determination is attended with peculiar difficulties. 

 Here again the older estimations of Murray and Irvine'' are 



^ Vergl. Phys. Stojf'wechsels, pp. 8-10 ; and " Der Stoiihaushalt des Meeres," 

 Zeitschr. Allgem. Phys. Bd. vii. 2 and 3 Heft, 1907, p. 328-9. 



2 " Hydrologische Untersuchungen," Bull. Acad. St Petersburg, Bd. xxiv. 1878. 

 See also Brandt. 



•^ See Brandt, Rapjyts. Proc.-Verb. vol. in. Appdx. D, 1905. 



•* Proc. Roy. Soc. Edinburgh, vol. xviii. 1892. 



